Like most battery packs we're seeing these days, uNu's 5000mAh Enerpak Tube ($60) and 11000mAh Enerpak Vault ($80) don't come with built-in Apple-specific cables or bundled Apple-ready cords. Instead, the units have USB ports -- one on the former, two on the latter -- so you can plug in your own cables for whatever devices you're looking to charge. Both do come with Micro-USB recharging cables, though, and each attracts dust and fingerprints very rapidly thanks to their glossy black plastic exteriors.

Enerpak Tube is physically smaller than Vault, measuring a little less than 4” long, 1.75” wide, and just shy of 1” thick. Its single USB port supports 1A charging, enough to power iPhones and iPods at full speed. To the left of that output is the Micro-USB recharging port, and underneath the two is a flashlight that can be activated by double clicking the power button, which is located along the curved edge. While flashlights are shrug-worthy additions to batteries if there’s little to no extra cost involved, the feature generally seems superfluous. You can tell approximately how much power is left on Tube thanks to a multicolor LED array.

The larger Enerpak Vault shares the same kind of black and silver casing, although it’s more boxy, resembling a plastic version of Just Mobile’s Gum Max. It’s 4.75” long, 3.25” wide, and about 1” thick. uNu augments the pack’s 1A port with a 2.1A port that’s capable of charging iPads at full or nearly full speed. There’s no flashlight, but Enerpak Tube’s plastic power button and multicolor LED are replaced by a round, swirled-metal button and four green LEDs under the plastic. Neither feels as nice as Just Mobile’s batteries, but at the same time, neither feels cheap. The green LEDs similarly don’t look fantastic, but they’re not awful, either.

Our iPad recharging results with Enerpak Tube and Vault were reasonable and great, respectively. Although we’d generally test a 1A battery with an iPhone, we used an iPad mini to evaluate Enerpak Tube because of the battery’s 5000mAh capacity, which seemed a good match for the iPad mini’s 4490mAh cell. With the tablet powered on, connected to Wi-Fi, and no music or video playing, Tube was able to deliver a 67% charge to the iPad mini—not bad, but not particularly efficient, either. Additionally, the recharging process took almost three hours, a figure which would’ve been halved if Tube supported 2.1A charging. On the other hand, iPhone users should be able to expect at least two full recharges and some change with Enerpak Tube. By comparison, the 11000mAh Enerpak Vault was tested with a 11666mAh third-generation iPad under the same conditions. Vault delivered a 70% charge to the power-hungry iPad, which is about 10% higher than we would’ve expected based on past battery testing results. Fourth-generation iPad owners should expect similar recharging performance.

Both versions of Enerpak are value priced, reasonably well built, and perform generally as expected—Enerpak Vault is actually pretty impressive. If you prefer a metal or matte housing to the shiny plastic, they may not be for you, but both have the energy to keep your iOS devices going. Enerpak Vault earns an A-, since it delivers a ton of iPad-ready recharging power at an unusually affordable price. Enerpak Tube, on the other hand, earns a general recommendation. A 2.1-Amp port and greater charging efficiency would’ve made it significantly more valuable, but it’s still a good option.

Editors' Note: iLounge only reviews products in "final" form, but many companies now change their offerings - sometimes several times - after our reviews have been published.
This iLounge article provides more information on this practice, known as revving.